Preparation of metallic salts of dicarboxylic acid esters of cellulose



Patented June i aoazsu PATENT OFFICE mums or METALLIC ssurs or m- :cansoxruo som names or, CELLU- (larlJtMalm and Charles B. Fordyce, Rochester, f N.Y- Y .,,assignors, by mesne assignments. to Kodak Company, Jersey City, N. J.,

a corporation of New Jersey i Serial No. scones No Application September 28. 1938,

c claims. (Cl. 260-101) wing an ester of that nature with an inorganic a solution of 201105-01 sodium bicarbonate inwater-soluble hydroxide which process is disclosed and claimed by C. J. Malm and C. E. Waring in their application Serial No. 627,149 filed July 30, 1932. Although this process has 15 been found to be satisfactory for the preparation of salts of the dicarboxylic acid esters of cellulose it does have the disadvantage that the alkali must be added very slowly or partial saponiflcation of the ester may take place. Thus, although this method is practical when care is exercised, production may be facilitated by our improvement.

One object of our invention is to provide a process for the preparation of salts of dicarboxylic acid esters of cellulose in which the ester may be subjected to the action of the total amount of reagent initially. Another object of the invention is to provide a process for the preparation of inorganic salts of dicarboxylic acid esters of cellulose which consumes less time than that in which an alkali hydroxide is employed. Other objects will appear herein.

We have found that an inorganic salt of a dicarboxylic acid ester of cellulose may be prepared easily and quickly by treating the ester withv an aqueous solution of 'a weakly basic salt.

We have found that many of the carbonates of the alkali metals are especially suitable for use in this connection.

The following examples illustrate processes which embody our invention:

Example I 400 lbs. of water was prepared and 8 lbs. :of butyl alcohol were added thereto. 100 lbs. of a cellulose acetate phthalate having 35% phthalyl content were stirred into this mixture and the stirring was continued until the ester was all dissolved. Carbon dioxide was given oil which tended to cause foaming, however, this was not excessive due to the presence of the butyl althe solution was filtered cohol. After the solid had completely dissolved,

and the filtrate was allowed to stand until free from bubbles. The cellulose acetate sodium phthalate formed may be separated from the solution by pouring the mass into an excess of acetone or it may be employed directly for any purpose for which an aqueous solution of this salt is desired. As the acid radical of the sodium bicarbonate is converted to carbon dioxide and passes oil as a gas there is no other contaminating material formed in this reaction. f

Example 11 Example III It is highly desirable in the carrying out of the present process that the basic reagent be added in an amount which will just neutralize the free carboxyl present in the dicarboxyllc. acid ester of cellulose employed. The advantage of this procedure may be seen when it is noted that when both the ester and the bicarbonate are completely consumed in the reaction, the resulting mixture consists only of the salt formed and water, perhaps with a little anti-foaming agent. It was decided to employ 37.4 lbs. of a fully esterifled cellulose acetate succinate in which of the total acyl content was succinyl. It was calculated that this ester would require 10 lbs. of sodium bicarbonate to form the sodium salt of the ester. were dissolved in 200 lbs. of water containing a little butyl alcohol. The acetate succinate was stirred into the solution until it was completely dissolved. The solution was then filtered and it now constituted an aqueous solution of cellulose vention may be represented by the formula in which represents the 0. portion of a cellulose unit, x

10 lbs. of sodium bicarbonate O-Ao + NsBCO -0 given 011 is not inert in the same sense as 002 nor is it as insoluble in water as is CO2 so that its presence in. the completed reaction mass is to a certain extent undesirable. Salts of alkali g" metals which are combined with strong acidsoneness group or simple esters of cellulose in which the only ucyl therein is a particular dicarboxylic acid radical. Obviously a cellulose ester containing two diiierent dicarboxylic acid radicals would also $3 The reaction which takes place in a process of be suitable for use as a starting material for a preparing cellulose sodium succinate, using soprocess embodying the present invention. dium bicarbonate ght be represented by the The water soluble salts of the dicarboxylic acid following equation: esters of cellulose have it found to be valuable, so

- H-00 m-o-oi (om)i /(OHI)I ---o o-c so 0 so --OH 0 BNEHOO: OH 0 200, 2330 o-o o-c i)u a)t H0C\ nt-o-o 35 r. 7 \9 v I 7 It is to be understood that the above formulae when employed in conJunction with a dye, for are illustrative and that the content. oi dicarthe backing of photographic film to form an an- 40 boxylic acid groups in any cellulose ester cannot tlhalation coating thereon. Because of its water 40 be predicated on the proportions oi the acyl sdoluliilgy this colored layer is removed in the gmups which are shown in these formulae, eve 0 ng of the film so that the use Of a film Although sodium. bicarbonat and diu having this antihalation coating requires no more b t are th preferred salts for use in processes than the ordinary processing to convert it into a embodying-our invention due to their inexpensatisfactory photographic sa 45 siveness, suitability and their formation 01' cargraphic mm containing an anmmmtmn hon dioxide and water any other which is coating is and claimed in U- S. mildly basic but which does not have sumcient :g g:- g g g eh m basici to remo he i e w a su 3 g g; fi g gi gi z g' :g adhesive compositions or as a vehicle for carry- 50 salts which we have found are suitable for use in dyes Pigments Wm suggest themselves our invention are. mom and dbsod'mm gse where water soluble cellulose derivatives are Dhates, sodium borate and sodium bisulnte or g h l u 0 their; equivalent salts oi potassium. .Due to their, I f p as 1,1 23% an n u metal 55 3X3 22 the sodium or the potassium salts salt of a, cellulose ester containing a dicarboxylic ually employed, however, it is to be understood that the acid radical having a free carboxyl group which corresponding salts of the 7 0th comprises treating that ester with a weakly basic mu-metals my beempmyed alkali metal salt in an amount approximately sired when phosphate or bomte molecularly equivalent to the free carboxyl of 60 ployed, the phosphoric .or boric acid formed as a the ester whereby hydrolysis of the cellulosic result of the reaction will be present in the compound mavomei aqueous solution and as the separation oi the 2. The process of preparmg an alkali metal 5911mm ester salt those acids salt oi a cellulose ester containing a fatty acid 65 bewmia Problempreferring, a radical and a dicarboxylic acid radical having a 65 Salt which forms an acid which breaks 9 free carboxyl group which comprises treating that a and Water may b9 readily seen- AmmuBh ester with a weakly basic alkali metal salt in an sodium bisulflte answers this description and has amount approximately molecmarly equivalent t been found sui for Processes embodying t the free carboxyl of the ester whereby hydrolysis present invention, the suliur dioxide which is of the cellul'csic compoundisavoided. 7o

, 3. The process of preparing an alkali metal salt oi a cellulose ester containing a. dicarboxylic acid radical having a free carboxyl group which comprises treating that ester with an alkali metal salt of carbonic acid in an amount approximately molecularly equivalent to the free carboxyl of the ester whereby hydrolysis of the cellulosic compound is avoided. a

4. The process of preparing an alkali metal prises treating that ester with a weakly basic alkali'metal salt in an amount approximately molecularly equivalent to the free carboxyl of the ester whereby hydrolysis of the cellulosic compound is avoided. 8. The process of preparing an alkali metal salt of acellulose ester containing a suocinyl radical having a free carboxyl group which comprises treating that ester with a weakly basic alkali metal salt in an amount approximately moleculariy equivalent to the free carboxyl of the ester whereby hydrolysis of the cellulosic compound is avoided.

CARL- J. MALM.

CHARLES R. FORDYCE. 15 

